This study aims to implement of Problem Based Learning combined Think Pair Share in order to improve critical thinking and science process skills of students at XI IPA SMA. This research was classroom action research. The subjects were 28 students of classroom XI IPA 1 SMAN 1 Kasiman Bojonegoro 2016/2017. This research was conducted in two cycles. The research data consists of the learning realized by observation, the results of the critical thinking paper and pencil tests, and the science process skills by observation. Data were analyzed by descriptive qualitative technique. The results showed that the combined PBL and TPS learning model can improve the ability of critical thinking, and science process skills students of classroom XI IPA 1 SMAN 1 Kasiman Bojonegoro. Penelitian ini bertujuan untuk menerapkan Problem Based Learning dipadu Think Pair Share dalam rangka meningkatkan kemampuan berpikir kritis dan keterampilan proses sains siswa kelas XI IPA SMA. Penelitian ini merupakan penelitian tindakan kelas. Subjek penelitian adalah siswa kelas XI IPA 1 SMAN 1 Kasiman Bojonegoro tahun pelajaran 2016/2017 dengan jumlah 28 siswa. Penelitian dilaksanakan selama dua siklus. Data penelitian terdiri atas hasil observasi keterlaksanaan pembelajaran, hasil tes tulis kemampuan berpikir kritis, dan hasil observasi keterampilan proses sains. Data dianalisis secara deskriptif kualitatif. Hasil penelitian menunjukkan bahwa model pembelajaran PBL dipadu TPS dapat meningkatkan kemampuan berpikir kritis dan keterampilan proses sains siswa kelas XI IPA 1 SMAN 1 Kasiman Bojonegoro.